1. Filed of the Invention
The present invention relates to a switch device, and more particularly to a switch device which performs a switching operation when its operational lever is operated in a rocking manner.
2. Related Art Statement
Switch devices of a type, which is switched on/off when its operation lever is operated in a rocking manner, have been used as, for example, switches for opening/closing power windows of automobiles. FIG. 15 is an exploded perspective view which illustrates the structure of a switch device of the aforesaid conventional type. An operation lever 2 formed into a substantially rectangular-shape is provided in such a way that it can be rotated around a support shaft 1. The operation lever 2 has three fastening holes 2a in the bottom surface thereof, the fastening holes 2a respectively accommodating corresponding drive rods 6 to 8 while interposing springs 10 so as to be elastically pressed. A lower case 12 of the switch device has a projection 13 secured to the top surface thereof, the projection 13 having, on the top surface thereof, a substantially V-shaped slide surface 14 while making its central portion to be the lowermost portion. The slide surface 14 has, on the two end portions thereof, steep clicking surfaces 14a and 14b. That is, the slide surface 14 is formed by two kinds of steps composed of a first step adjacent to the central portion of the slide surface 14 and second steps formed at the two end portions of the same.
Furthermore, the projection 13 has movable contacts 15 and 16 on the two sides thereof while being respectively supported by support plates 3. The lower case 12 has fixed contacts 17a and 17b on the surface thereof in such a way that they confront the two end portions of the movable contact 15. The lower case 12 further comprises fixed contacts 18a and 18b on the surface thereof in such a way that they confront the two end portions of the movable contact 16.
In the aforesaid conventional switch device, the movable contact 15 pressed by the drive rod 6 is positioned in contact with the fixed contact 17b and the movable contact 16 pressed by the drive rod 7 is positioned in contact with the fixed contact 18a in a state where the operation lever 2 is at the neutral position. When the operation lever 2 is rotated clockwise in a direction designated by an arrow .theta. shown in FIG. 15 in the aforementioned state, the drive rod 8 slides on the slide surface 14 toward the clicking surface 14a until it reaches the clicking surface 14a at which the sliding resistance will be changed. As a result, the clicking touch can be confirmed. Immediately after this, the movable contact 15 is pressed by the drive rod 6 and is thereby rotated until it comes in contact with the fixed contact 17a. Therefore, the switching operation is performed. Although the rotation of the operation lever 2 also moves the drive rod 7 toward the fixed contact 18a on the surface of the movable contact 16, the movable contact 16 is not rotated due to this movement.
On the other hand, when the operation lever 2 is rotated counterclockwise in the neutral state, the drive rod 8 slides on the slide surface 14 toward the clicking surface 14b until it reaches the clicking surface 14b at which the clicking touch can be confirmed. Immediately after this, the movable contact 16 is pressed by the drive rod 7 and is thereby rotated until it comes in contact with the fixed contact 18b. Therefore, the switching operation is performed. Although the rotation of the operation lever 2 also moves the drive rod 6 toward the fixed contact 17b on the surface of the movable contact 15, the movable contact 15 is not rotated due to this movement. The aforesaid switch device can be used as, for example, a switch for a power window for an automobile. In this case, a manual operation for opening the window to an arbitrary degree is performed at the first step and an operation of fully opening or fully closing is performed at the second step.
The conventional switch device enables the predetermined clicking touch to be realized by the shape of the slide surface 14 of the projection. Therefore, the degrees of the clicking touch cannot easily be varied. Furthermore, since the three fastening holes 2a must be formed in the operation lever 2 and the fastening holes 2a must accommodate the springs 10 and the drive rods 6 to 8, an optical path cannot be formed in the operation lever 2. Therefore, an illumination type switch cannot be realized. Furthermore, the slide surface 14 wears down whenever it is used, causing a problem of durability to arise.